This assembly is from 1957 from a Raytheon manual, but can be modernized using a BC548, 6 V power supply and common 100 mA relays.
Here is an interesting game found in a 1992 technical documentation. In this game, a set of 9 red...
We found this circuit in an old documentation from 1979. It is a logic level tester that is...
This circuit is from the 80's but uses common components today. The relay is voltage sensitive...